Centrifuge



June 13, 195o A. F. HOWE l 2,511,585

CENTRIFUGE Filed Jan. l0, 1946 3 Sheets-Sheet l l W T-A B6 B7 2.5 l

u 4 as /ee 65 F I G l 5\\\|||||l1r`\\\\\\\.\ I I u as 75 I ,53

ANDREW F HOWE mm@ ATTORNEY `[une 13, 1950 A. F. HowE 2,511,585

CENTRIFUGE Filed Jan. 10, 1946 3 Sheets-Sheet 2 FIG.2

' INVENTOR ANDREW F. HOWE ATTORNEY June 13, 1950 A. P YHowE v 2,511,535

CENTRIFUGE Filed Jan. 1o, 194e Y z' sheets-sheet s 26 Flc. 3 Il \\\\\/.31

ANDREW F. HowE ENl ATTORNEY Patented June 13, 1950 UNITED STATES PATENT OFFICE Andrew F. Howe, St.` Louis, Mo.,assignor to Centrfugal & Mechanical Industries, Inc., St. Louis, Mo., a corporation of llVIissoul'i Application January 10, 1946,'Serial'No. 640,209

4 claims. 1

This invention pertains to centrifuges generally and concerns itself more particularly with centrifugal driers and clariers used inV separating solids from iluids in which they are suspended or immersed. i

In various industries it is often necessary to dry substances in large quantities and under conditions which make it infeasible to expel the moisture by heat or similar conventional methods. This is particularly true in the coal industry where washed coal is processed for use in refractory lined furnaces. Here it is necessary to dry the washed coal until its free moisture content is less than nine per cent, since water quantities greater than this will damage the refractories to the extent that the fuel cannot be used.

Because of the large quantities to be dried, the economies involved and other factors, such as continuous handling, centrifugal driers have been found particularly suitable for drying coal, and machines have been developed for this purpose.

Two problems have been presented in this particular process with the solution of which the instant invention deals. And while these problems may be introduced, by Way of example, in their connection with coal drying, they are present in the'same form in numerous other industries.

Thus, where the substance washed contains finely divided particles which are carried oiin the Washing fluid as waste in substantial amounts, it is desirable that this Waste be reclaimed. Also, in some localities, it is necessary that the washing uid itself be reused. With present equipment and methods neither of these desired results have been realized within economic limits making them feasible.

With the satisfactory solution of both of these problems as a desired result, it is a general object of the instant invention to provide a centrifugal separator which will remove substantially all of an immersed solid from its immersing fluid.

nessA and subsequently mix the separated solids into a composite mixture.

Still another object of the invention is to provide ka centrifugal separator which will clarify an immersing fluid of solid matter to Within less than one per cent by weight of the liquid.

. Yet another object of the invention is to providea centrifugal separator in which solids down to a predetermined minimum size are removed continuously from an immersing fluid by centrifugal` screening and solids below said predetermined size are removed continuously from the fluid by solid bowl centrifuging.

A.It isa further object of the invention to provide a centrifugal separator having a solid bowl and ascreen type centrifuge arranged coaxially and driven from a common source.

' A further purpose of the invention is to provide a `centrifugal i separator having a centrifugal screen fand' a solid bowl arranged to be rotated about a common axis at a given speed and separate.V nights operative in conjunction with the screen and bowlalso adapted to be rotated about said common axis and at a slower speed than said bowl and screen.

uFurther still, it is an object of the instant invention to provide a continuous centrifugal drier and clarifier having both a screen and solid bowl type centrifuge mounted coaxially and arranged to operate in series and having separate Scrapers or wipers rotatively associated with both centrifugesr arranged to operate at a speed differential and at a selected pitch whereby the degree of yseparation of a solid and its immersing fluid may be controlled.

Other objects and advantages will become apparent as the description proceeds and a more comprehensive understanding of the invention will be -afforded from the following detailed specicationjvvhen considered in conjunction with the accompanying drawings in which vFigs. 1 and 2 are vertical sectional views of a continuous centrifugal separator embodying the instant invention showing in elevation the left and right half sections thereof, respectively, as divided along a` line Ap--A taken through the vertical axis of the machine.

Fig. 3 is an elevationalv view of a housing member incorporated in the machine showing its mountings, and

.'Fig. 4' is a partial sectional view of the machine taken along the lines 4-4 as indicated on Figs. land?.

WWith` reference to Figs. 1 and 2 of the drawings, theinvention contemplates a heavy frame II upon which all of the operative mechanisms are carried. This frame, which is substantially square, may be fabricated from structural steel members of desired sizes and weights. The machine is supported on four uprights, two of which are shown. These uprights I2 and I3 are fitted with base plates I4 and are connected by a pair of principal cross members I5 and I6. uprights not shown are connected by similar cross members and both of these assemblies are connected by four I-beams I1, I8, I9 and 2I.

A motor mounting frame fabricated from three angle irons 22, 23 and 24 (Fig. 2) supports an electric motor 25 providing` power for' driving the machines centrifugal separators. l

A housing 26 (Fig. 3) is supported in the' frame II in which a sleeve shaft 21' and' a solid shaft 28 (Figs. 1 and 2) are journalled for rotation.

This housing takes the form of a hollow truncated the housing and provide support for a' scraping mechanism later to be'd'escribed.

The center of the housing is occupied :by a wellv 36, the walls 31 of which enclose two bearings'- 38 and 39 for the sleeve shaftv 2'1. This particu-'- lar shaft is directly driven by the motor 25, which mounts a pulley wheel 4I on its shaft 42. A

complementary pulley wheel 43 is keyed to they sleeve shaft 21, and is driven by a compound V- belt carried over both pulleys.

The solid shaft 28 is driven at a different speed than that of the shaft 21 through a dif.

erential generally designated 44. This mechanism is contained in a suitable housing 45' in which a shaft 46 is journalled for rotation in two bearings 41 and 48. To the shaft 46, two gears 5I and 52 are keyed to rotate therewith. The first of these gears meshes with a gear 53sp1ined to the sleeve shaft 21 and the second with a hubbed gear 54 xed to the solid shaft 28. This latter shaft terminates in a thrust bearing 55 and' is supported in the sleeve shaft 21 by' a bearing 56. A difference in the size of theL gear 54- from' that of the gear 52 provides the speed differen-r tial between the two shafts. Obviously` they both rotate in the same direction.

Upon the upper end of the sleeve shaft 21 there is mounted a large wheel-like mem-ber, the hizb` 51 of which also' takes the form of a hollow truncated cone. Radially projecting from the hub 51 are a plurality of spokes 58` which connect the same with a flanged rim 59. The base of a perforated conicallyl shaped membery 6I',`

commonly referred to as a basket,` rests' in the flange of the rim 59 and' within thisbasket is fitted a screen 62, which conforms substantially' to the configuration of thev basket. The top of the basket 6I is bearinged against the extern-al` surfaces ofY a feed spout 63 which rotates within an opening in the top of the basket. The* ar-'` rangement of the basket and screen are more fully described in a patent to Andrew F".4 Howe,

No. 2,321,207, filed August 25, 1941. f

Also carried on the rim 5-9 and supported for rotation therewith is a solid bowl? compartment 64 which is 'provided with a top 65 also bearing against the feed spoute53 inorder that the latter may rotate in the former's central opening'.

The two They Slpig Sides" Near the outer edge of the top, a series of openings 66 are made which form a lip 61 around the wall of the solid bowl compartment at its top. In this instance, the solid bowl compartment is secured to the rim 59 by a number of brackets 68 placed at spaced intervals around the base of the lbowl.

With the above described arrangement of the parts it will be noted that the solid bowl 64, the .basket 6I, and the screen 62 are rotated at the same speed by the rim 59 as driven by the sleeve shaft 21.

By similar means a flight 69 operating in connection with the bowl 64 and a flight 1I operating L in conjunction with the screen 62 are driven at the same' speeds by the solid shaft 28. Here the Hight 1I is supported on a hub 12 by a series of spokes 13. The hub itself is keyed to the shaft 28" and is bearinged for rotation in the hub 51 by a bearing 14. The top of the flight 1I is bolted tothe bottom of the spout 63 thereby providing a driving connection for rotating the spout.A

The flight 69, on the other hand.. is secured to thev spout 63 by a plurality of pins 1.5 andi is rotated therewith.

Each ii-ight is made up of a series of: Scrapers which may range' from. straight members toy helical. members of two or more turns. In the illustrated embodiment the Scrapers are shown in: the form of helicesl and for the flight 69 are designated by the numerals 16, 11, 18, and 19. TheI ight1l ismade up with a group of Scrapers' 8|,vr 82, 63, and 84. In, each instance the respective Scrapers carry the solids downwardly from the bowl and; the screen and the degree of moisture separation therefrom is a function of the number of turnsv of the iiig-hts andA theV speed differential between the sleeve shaft 21 and the solid shaft 28. I

Surrounding the solid bowl compartment 64 is a launder into which the immersing fluid is discharged after the solid matter hasy been separated therefrom. This sluice or trough is xed to the frame IIvv and is provided with. a removable cover 86. Located centrally in this cover is ak funnel. 81 into which the mixture of solid matter and its immersing fluid is continuously fed. This funnel discharges into the spout 63 from which the mixture is thrown by centrifugal force out through a series of openings 88 in the bottom thereof. A, dlct 85a carriesY the clarifiedA fluid' from the launder 85 to a point where. it may be reused' or discarded.v

The solidsfrom the bowl compartment are discharged through the spaces existing between the brackets 68 and from the screen 62 through the' spokes 58', and are. collected in a large circular cage 89, also xed' tothe frame' I I.

Initially, the solids' froml the screen 62 are thrown in an annular pile QI` at the outer extremities of the cage 39. As the pile is built up; these solidsrfallt by gravity into the path of a plurality orrotating Scrapers 92, which convey' themrto' a'- discharge opening 93" in the`A bottom of' theA cage 88 from which point they may bey coni tinuously moved by any suitable means.

The solids from the bowl, on the other hand,

may be* collected if desired onl a rotary conveyer il-support'ed'on the Scrapers 912'. From thisfcon- '.lveyer these solidsA are plowed' by a stationary plow fixed to the framef- Ill; into. a second dis@ charge opening in the. cage 82E-f formed by anincl-il'ne'd. wall' 96: thereof L` Both.v the Scrapers Stand the rotary conveyerv 41 arev driven at arelatlvely' slow speed; from the'same pcwersource.f Thusfthe Scrapers.` 92A are fixed ats'paced intervals to a conically shaped apron 91, which is supportedlvforvrotation on atruckring 98; This ring'carries an-Aoutwardly extending flange S on the undersideV of which is a circular boss IBI which rides on the trucks 34,previouslydescribed i A separater-power' .source ytaking the form of .an electric motor |02 (Fig. 1)is usedVto-drive the ring 98. This motor, through a gear box |03 turns a shaft |:04Mon Lthe end -ofwhich `is keyed a Aspur gear `|05 (Figs.y l and). *The-teeth of this gear engage'in and mesh with a circular band'of 'teeth |06 forr'nirigalpa'rt of the ring 98 to rotate. both 'the scrapers 92` and the rota conveyer 04 fixed thereto.

The conveyer `l-)Zlis supported for rotation about `the rim 59 on a series of brackets |01 formed from three angle irons |08,` |00, and each braclgetbeing fixed to oncofthe scrapers02.

Where it is desired tomix the fine solids discharged from the bowl 64 with those of coarser nature from the screen 62, the rotary conveyer 94 together with its supports |01 may be removed. In such case the ne solids will fall `onto-,the apron' 101 and will be mixed with the solids from thescreenf62.

Operation Y;

While the operation ofithe machinemay be readily understood from the foregoing'description, a complete cycle of` operation will be summarized. First, l the-motors `25 `and |02 4are started and the machine brought up to operating speed. Vv'Ihen the mixture of the solids and immersing' fluid, which is -to be processed, is introduced into the machine continuouslythrough the funnel'fli'i.v From the spout 63, into which the funnel empties, the Imixture is thrown by centrifugal force out through the openings 88 in the bottom thereof against the screen 62 on the inside of the rotating-basket 6|. VB'yf centrifugal force, theliquid or immersing fluid, together with such of the solid matter as 'will pass the screen, is forced through the perforations of the screenand basket and in'to the solid bowl compartment |54. 'l "1 I'n lthis first of the Acentrifuging operations about eighty-five to ninety-five per cent of the solids may be removed. These solids which do not pass the screen E2 are moved downwardly by the scrapers 8|, 82, 83 and 84 of flight 1| which is rotating at a different speed from the screen 62. The time during which the solids are retained in the screen determines the degree to which they are freed of the immersing fluid, since they constantly become drier as they approach the bottom of the screen. Thus if the scrapers 8|, 82, 83 and 84 are single turns, that is, if they circumscribe the flight 1| once in traversing its length, and if the speed differential between the screen and its night is one revolution per minute, then each scraper will move its cargo of solids through the screen in a minute. The solids thus processed would be drier than would those processed by a half-turn flight which would carry them through in thirty seconds. Likewise if the speed differential were charged so that the flight would turn more rapidly relative to the screen the drying time would be decreased. The same is true of the flight 69 and the bo'wl 54.

Returning to the fluid which passes through the screen 62 and the basket 6|, it strikes the inside surface of the flight 60 and is forced downwardly and out into the bowl compartment 64. This liquid, .containing a 'relativelyrsmall percentage of the extremely finely divided particles of the solid matter is centrifuged in the `bowl 64 which revolves at the same speed asthe screen 62. Here, however, the-peripheralspeedof the bowl is much higherduextoits larger diameter, which condition gives to it a centrifugal action that causes the fine solids'to4 be forced against the wall of the bowl'wherethey are scrapeddownwardly by the flight 69.. g 1 The'I fluidvthusfreed from substantially all of its solid matter, is forced upwardly along the bowl until itis whipped out through the openings 66 in its cover 65., After it iis expelled from the bowlV itis collected. in the launder as a fluid substantially free of solid matter.

4The solid matteris collected in a manner previously described in the cage 89n Its degree of drynesswill have been determined by the flights selected and-,the speed differential.

- -In conclusion some of the features of the invention may be better understood by considering them in connection with a specific application. Thus in the drying of washed coal, and with properly selectedflights and speeds, the fines may be separated out and processed for pulverized fuel, or other` uses,.or they maybe vmixed with the coarser coal. In the latter case, although the fines .may contain as high as'seventeen per cent moisture,.the composite fuel `will have much less than the critical nine per cent moisture content.

The economies involved may well be appre-k ciated if coal containing six per cent of flnes is processed in the machine at its maximum rated capacity of eightyftons per hour. `In one run of twentyfour hours, some one hundred and fifteen tons 4of coal heretofore wasted would be reclaimed. Moreover, in'communities where washing water is at a premium, the 'clarifiedwater discharged frorn the launder of the machine could be yused again, sinceit can be cleaned of solid.

matter to within'one-half of one per cent. Water containing up to one per cent may be reused.

'Whilepa specic embodiment of the invention hasibeenvillustrated andA described, it is apparent that the same.' may be practiced in other ways without departing from its basic concepts. Accordingly, the' recitations Vand representations herein' madev areto be interpreted as illustrative only and not in a limiting sense, and, insofar as the changes and embodiments to which the invention is susceptible fall within the scope of the appended claims they are included as if described.

What is claimed is: e

1. In a centrifugal separator, a rst and second vertically disposed shaft supported in a frame for coaxial rotation, said first shaft rotating within said second shaft, a, basket supported on an end of said second shaft for rotation therewith, a conically shaped screen supported on said basket for rotation therewith and adapted to receive continuously a charge of fluid having separable matter contained therein, a solid bowl taking the form of an inverted truncated cone surrounding said screen and supported on said basket to rotate therewith, separate Scrapers mounted for rotation on said first shaft and adapted to scrape the inside walls of said screen and said solid bowl, respectively, and means for rotating said first and second shafts at different rates of speed whereby said screen and said solid bowl are rotated at the same rate of speed and said Scrapers Vare rotated at a common speed but different from the rate of rotation of the bowl and screen.

2. In a centrifugal separator, a solid bowl tak..

maintes:

7. ing .the form of. an inverted. trimcated conemounted for rotation, about a. vertical axis, a conically shaped. screeni mountedi for rotation.v Within said solicly bowl about the lattensaxisy of rotation and adapted to be continuously charged with a iluid` containing separable matter, said screen" and said bowl being: rotated at the same. rate off speed, a first scraper comprising a solid conically shaped. body and a plurality of. scraper' blades mounted thereon, said latter elementsbe-v ine adapted: to scrape the inside" walls or said screen., a second; scraper comprising a` solid con ically shaped body' adapted to extend' in the form. of a solid apron substantially over thev external: area` of said. screen but disposed at a,` distance therefrom and a plurality of scraper' blades. mounted on` said second scraper adapted to scrape the internal walls of said solid bowl, and means for rotating said first and second Scrapers at a common speed differentY fromthecommon speedl at whichr said screen and said solid bowl are rotatedf 3. In a centniifugal separator, a sol-id bowl tak'- ing the form of an inverted. truncated cone mounted for rotation about a vertlcalaxis, a conical-lyv shaped screenmounted for rotation withinv said solid bowl about the latters axis of rotation and adapted to be continuously charged with afiuid containing separable matter, said screen and said bowl being rotated at the saine rate of speed", separate Scrapers' mounti ed to rotate at the same' rate of speed but different from that of Asaid screen and said bowl, said Scrapers being operative to scrapeI the inside walls of' said bowl and said screen whereby they said separablematter is discharged aty the bottom of said bowl and said screen, and first andsec'ond collectors, each rotatabl'eabout an axiscoinmon to the axis of rotation of said bowl andsai'd screen for separately collecting the separable matter discharged from. said bowl and from said screen.

4.111 a centrifugal separator,v a solid bowl taking the form of an inverted truncated coney mounted for rotationabout a vertical axi's, a conically shapedl screen mounted' for rotation within said bowl about the latter's axis of' rotation, a tubular spout arranged concentrlcally with said axis and constructed and arranged. to

continuously charge the screen. with a fluid containing separable matter, separate Scrapers mounted to rotate about-said axis, driving means for: said. bowl.. screen. and. Scrapers constructed and arranged to drivethe Scrapers at different rates than the bowl and screen respectively, said Scrapers being operative tcrscrape the inside walls of said. bowly and said screen whereby the said.

separable matter is discharged at the bottom of said bowland said screen,.and.rst and second collectors, each rotatable about an` axis common to the` axis oifcrotation of said bowl and said ,tscreen for separately collecting the separable matter discharged. from. sai-d bowl and from said screen.

ANDREW FlHOWE.

REFERENCES- CITED The following references are of record. in the le of this patent: f

STATES PATENTS Number Name Date 8531583 Guttn'er et al. May 15, 1907 924,376" Phillips June 8, 1909 1,244,007 Wendell Oct. 23, 1917 1,415,939 Maby May 16, 1922 1,839,941. Zelenznials Jan.` 5, 1932 1,991,490 Brewer Feb. 19, 1935 2,043,661. Howe: June 9, 1936 2,043,662 Howe June 9, 1936 2,095,206 Sharples Oct. 5, 1937 2,184,598 Jahnv Dec. 26, 1939 2,239,992l Corwin Apr. 29, 1941 2,308,557 Winkler Jan. 19, 1943 2,370,353 Howe Feb.l 27, 1945 FOREIGN PATENTS Number Y Country Date 6,167 Denmark n Nov. 25, 1903 202,489 Germany 1 Oct. 5. 1908 26,127 Great Britain Nov. 14, 1913 291,930 Germany May 16, 1916 347,985V Great Britain May 7, 1931V 761,586 France Jan-r 10, 1934 810,862- France Jan. 6, 1937 

